Logic Express 9 - missing loops

I've recently installed LE 9.1.8 on a new Mac mini (2.3 GHz core i7, OS X 10.9.3) and can't get Apple loops to work. The loops are there in Library/Audio/Apple Loops just like they should be, and Garage Band loops appear in GB. But in LE, nothing. I'm pretty sure they were there when I first installed the application, but the first time I went to browse the loops, everything was greyed out. Now, each time I launch LE I get a message that no Apple Loops were found and I should reinstall them.

I've read a lot of posts on Apple Support, and tried all the suggestions. Dragged my loops folder into the loops browser: asks for my admin password and looks like something is happening, but loops still don't appear. (Tried that lots of times.) Reindexed from within the loops browser: nada. Used Disk Utility to repair permissions on the disk - no result. Reset permissions manually in Finder: ditto. Forced Spotlight to reindex the loops folder: no effect. Reinstalled Logic Express: no change.

Don't know if it's relevant, but this is a reinstallation on a different machine. I had LE on a MacBook that was stolen, and I've installed from the same DVD on a new machine bought to replace the lost one.

I'm kind of stuck for what to do next. Anyone out there know a trick that works when all the above has failed?